Strange but true facts about the Human Body
The human body is a complex and intricate machine. As you read this page, your brain is taking written letters and transforming them into sounds, your heart is pumping blood to the rest of the body, your immune system is defending you from bacteria and germs, and your stomach is digesting the sandwich you ate for lunch. Let’s take a deeper look at some of the impressive parts of the human-machine.
1. Babies have more bones than adults. While adult bodies have 206 bones, babies are born with around 300 bones! Now, some of these “bones” are not the typical hard and strong bones you're probably thinking of. Many of a baby’s bones are made of cartilage, a tough and flexible connective tissue. Before birth, this cartilage plays an important role as it lends the baby the flexibility it needs to curl up within the small and tight space of the mother’s womb. After birth, as the baby grows and develops, this cartilage undergoes a process called ossification that transforms the connective tissue into harder bone. In addition, some bones will fuse together as the baby grows.
2. Estimates place the number of cells in the human body around 30 trillion cells! So far, scientists have discovered 200 different types of cells. Examples of cell types include neurons (brain cells), red blood cells, white blood cells, skeletal muscle cells, cardiac (heart) muscle cells, adipocytes (fat cells), etc. A stem cell is a particularly interesting type of cell. Unlike other body cells, stem cells are not originally given a specific role. Rather, they have the potential to become many different types of cells. Because stem cells have the ability to regenerate, restore, and repair cells, scientists hope they can be used to treat diseases such as rheumatoid arthritis, Parkinson’s, and Alzheimer’s.
3. Your brain cannot feel pain. Why is this? Within skin, muscles, joints, and some organs are specialized fibers, called nociceptors. When the body is hurt, these fibers are responsible for sending pain signals to the brain. Once the brain interprets these signals, you feel pain. The brain itself, however, does not contain any nociceptors. So, where do headaches occur then? While headaches feel like an attack on your brain, they actually occur in the layers of tissue between your brain and your skull, called the pia and dura.
4.Within your stomach is a digestive fluid known as gastric (or stomach) acid. This liquid is responsible for breaking down the food you eat. The pH scale, which measures how basic or acidic a fluid is, ranges from 0 to 14. Acids are fluids that score below a 7 on the pH scale, while bases are fluids that score above a 7. Compounds that score a 7 are neutral. On the pH scale, stomach acid scores about a 1 or a 2, which means it is very acidic. At its strongest, stomach acid can be nearly as strong as battery acid!
5.Heartburn is a burning sensation you feel in your chest after you eat. Heartburn occurs when stomach acid travels back up into the esophagus, the tube located between your mouth and stomach. Certain foods can trigger heartburn in some individuals. Examples of such foods include: spicy foods like raw onions, tomato products like ketchup, high-fat foods like cheeseburgers and fries, and citrus fruits like lemons and oranges.
6. Burping is normal and is a result of swallowing air as we eat. Burping is the body’s way of getting rid of excess air. When you drink soda, you may notice you burp a lot. This is because soda contains a gas called carbon dioxide. This gas does not usually enter your stomach because it is extra air that the body wants to get rid of. It stays in your esophagus until you burp it out.
7. Without a simple flap of cartilage, it would be very difficult to eat. This flap of cartilage is called the epiglottis. The epiglottis is located behind the tongue and in front of the larynx. The epiglottis prevents you from choking because it seals off the larynx when you swallow, keeping food from falling down your windpipe and into your lungs.
8.Humans may be the greatest endurance runners on Earth. While animals like cheetahs and horses are faster than humans in the short run, humans have many adaptations that give us an edge over these animals in the long run. For instance, we have millions of sweat glands all over our body that act as a very efficient cooling system. While dogs have to rely on moving air in and out of their mouths (panting) to cool down, our ability to sweat allows us to cool down and run simultaneously. Horses also sweat, but not as much as humans. In addition, unlike horses, humans do not have fur, so our sweat evaporates more efficiently than a horse’s. Our tendons, the connective tissue between bones, serve as another adaptation that makes us great distance runners. These tendons act much like springs, making it easy for our body to propel itself forward. Humans also have the ability to feel the “runner’s high,” a sense of euphoria or well-being people experience when certain hormones (body chemicals) are released during exercise. This runner’s high blocks out pain and motivates people to keep running.
9.The heart serves to pump and circulate blood and oxygen around an organism's body. The human heart has four chambers and several valves. The upper two chambers are called the atria, while the bottom two chambers are called the ventricles. The right side of the heart receives deoxygenated (oxygen-poor) blood and sends it to the lungs for oxygen. The left side of the heart receives oxygenated blood and sends it to the rest of the body. The process of moving blood through the heart, to the lungs, and to the rest of the body can be broken into four steps: 1) The right atrium sends deoxygenated blood through the tricuspid valve to the right ventricle. 2) The right ventricle then pumps the blood through the pulmonary valve to the lungs to receive oxygen. 3) From the lungs, oxygenated blood travels to the left atrium. The left atrium pumps blood through the mitral valve to the left ventricle. 4) The left ventricle sends oxygen-rich blood through the aortic valve to the rest of the body.
10.Your body has more than 600 muscles! There are three types of muscles: skeletal, cardiac, and smooth. Your skeletal muscles connect to your bones and help your body parts move. Cardiac muscle is found in your heart. As you know, you do not have to think about making your heartbeat, it does so automatically. This is because cardiac muscle is an involuntary muscle. Smooth muscles are also involuntary muscles because you do not have to consciously control them. They are found in the walls of hollow organs like the stomach, intestines, uterus, and bladder. Smooth muscles are so-called because unlike cardiac and skeletal muscles, smooth muscles lack striations (patterns of dark and light bands in the muscle tissue).
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